Archive for September, 2017:

2017-09-30 Zenith Royal 500 Radios  Pt. 02

Posted to FB group Vintage Transistor Radios  Oct 7 and after. Yeah, it’s a bit confusing because the number of IF transformers is one more than the number of transistors. When you work on IFs, what do you use for alignment?  I got Zenith Royal 500s that the previous owner apparently fiddled with the IF

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2017-09-29 Zenith Royal 500 Radios Pt 01

I bought a bunch of Zenith Royal 500 and similar AM transistor radios from an eBay seller.  These were made in the late ’50s to early ’60s.  They all use air variable capacitors like the 5 tube sets.  They all use four AAA cells for power.  The cases on some say unbreakable nylon, but there

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2017-09-23 Cellphone Charger Secret Circuit

Posted to FB Arduino group Sep 23 Mbihi Oliver Four hours is twice as long as 2 hours with the correct charger.  Here is a secret many don’t know:  Smartphones don’t necessarily charge at maximum, especially if they’re charged by a charger not made for their phone. Smartphones often have a sensing circuit that checks

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2017-09-21 Kid Was Totally Into Telephone Central Offices

Posted to FB Antique Telephones group as a reply to Kevin J. Fitzgerald  I helped some students in our computer lab, and one high school kid, I think his name was Robert, was totally into phones.  He had written a Basic program that printed a list out, with the various exchanges in the 714 area

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2017-09-20 Use LM7805 To Charge Phone?

I posted this comment to FB Arduino group 2017-09-22. “Can I use a 7805 (regulator IC) to charge my cell phone?” The output is 5 volts, which is what the phone needs to charge.  But the average smart phone will take more than 1 amp, up to 2 amps to charge quickly.  The 7805 can’t

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2017-09-19 Giant ‘Analog Meter’ For Clock Display 

FB comment “Brilliant!” Preet Sangha said, and I agree, but since I have a hard time seeing small meters across the room, I thought up another, bigger meter.  How about this? Instead of meters, use a printout of a meter face, full page size.  There will be one for each hour, minute and second.  These

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2017-09-18 Telephone Auto Ringdown Circuits

From my comments on FB Telephone group 2017-09-23 Hot ringdown?  We had dozens of elevator lines that were configured to call an answering bureau as soon as the phone went off hook.  I don’t know what the technical term for them is because our account reps weren’t the brightest and gave us some other term,

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2017-09-17 Telephone Loop Current And Security – DSL 

From comments in FB Telephone group 2017-09-24 Mark Grady I remember the site we had across the street from the Santa Ana Bush St. CO.  Just for grins I checked the loop current:  Fifty-five milliamps!  Couldn’t get any closer than that!  The problem is that all the switching equipment in COs seem to have been

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2017-09-14 Menu Display And Single Button Selection

I will post this to Facebook Arduino group. I’ve been thinking about how the cheap clock kit I built uses a single button to step through and set the hours, minutes and seconds.  It’s a bit tedious and it took me a bit of practice to get the hang of it.  But it makes possible

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2017-09-11 Cassette Tape Stuck In Player

From post in FB group Vintage transistor radios I need some advice.  I bought a Sony combo cassette player and AM/FM radio ‘boombox’ back years ago when it was new.  A few years later I put a cassette in it and played a recording of my now deceased parents.  I was listening when it started

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